Field of the Invention
The present invention relates to a surge absorber and a manufacturing method thereof, and more particularly, to a surge absorber having improved durability, since a ceramic tube formed of a ceramic material with excellent mechanical strength is used and the ceramic tube is joined to sealing electrodes by use of brazing rings, and stably used at a high voltage, since the ceramic tube is completely sealed, and a manufacturing method thereof.
Description of the Related Art
In general, a surge absorber is a device mounted on a region vulnerable to electric shock due to abnormal overvoltage such as lightning surge, static electricity, or the like to prevent a printed circuit board, on which electronic components are mounted, from being damaged due to abnormal overvoltage via discharge of gas that consumes discharge energy upon application of an abnormal voltage thereto. The surge absorber is installed at a junction between a transmission line and telecommunications terminal equipment such as telephones, facsimiles, and modems, or a driving circuit of display apparatuses such as TVs or monitors.
FIG. 10 is a sectional view illustrating a structure of a conventional surge absorber. Referring to FIG. 10, a surge absorber disclosed in Korean Patent Application Publication No. 2012-0097135 includes an accommodation tube 11 filled with an inert gas, a pair of sealing electrodes 12 disposed at both ends of the accommodation tube 11 and respectively electrically connected to lead wires 13, and a surge absorbing unit 15 electrically connected to the sealing electrodes 12. The surge absorbing unit 15 includes a nonconductive member 16, a conductive coating film 17 enclosing the nonconductive member 16, a protective film 18 protecting the conductive coating film 17 in a state of surrounding the conductive coating film 17, and a plurality of discharge gaps 19 dividing the conductive coating film 17 and the protective film 18.
However, in such a conventional surge absorber, a glass tube is used as the accommodation tube, and the glass tube is joined to the sealing electrodes by melting glass at a high temperature under the condition that the sealing electrodes are inserted into the accommodation tube, and thus sufficient joining strength cannot be obtained. In addition, a conventional surge absorber has insufficient durability due to low strength of the glass accommodation tube and low joining strength. Accordingly, the conventional surge absorber cannot be stably used at a high voltage.